This invention relates to sliding fasteners, such as zippers, and more particularly to improved terminals in those sliding fasteners wherein the two parts are routinely separated and rejoined, as for example, down the front of a coat.
A conventional separable zipper for a coat has a terminal at the bottom end of each half of the zipper. One terminal holds the zipper slider and will be referred to as the "slider terminal." The other terminal, which will be called the "free terminal" herein, is simply a pin with a shape slightly bent to fit properly in the slider. The slider terminal also includes a pin on which the slider rests. Rigidly connected to the slider terminal pin, at the rear of the slider, is a socket for receiving the free terminal pin. To join the terminals, the free terminal pin is inserted into the one front port of the slider which is empty. The fabric tape, or stringer, by which the zipper teeth and free terminal are connected together and to the garment, must be fed into the side slot of the slider at this point. Then the stringer is gripped to pull the free terminal pin all the way down into the socket of the slider terminal. It is usually necessary to grip both the free terminal stringer and the slide terminal to prevent the free terminal pin from rising out of the socket as the slider is being drawn away from the terminals to close the zipper. This gripping should be continued until a few of the teeth of the zipper are interlocked.
It is commonly recognized that the described process of closing a conventional coat zipper is not ideal, requiring a disproportionate amount of time, attention, and skill. The process is best carried out when the wearer is standing, so that the free terminal pin and the slider port and socket are roughly aligned for engagement. The wearer should pay reasonably close attention to the task and is preferably not running or walking, since the terminal parts are small and are not easily engaged when moving with respect to each other. The skills demanded represent a problem to small children, particularly the requirements of feeding the free terminal pin and stringer to a fully seated position in the socket, and then holding them there.
There have been various attempts to provide improved alternatives to the conventional separable sliding fastener. One example can be seen in U.S. Pat. No. 2,203,005 to E. Wittenberg, et al. There, one of the fastener terminals is provided with a pin which is oriented perpendicular to the plane of the stringer. The other terminal has a corresponding slot for receiving the pin and fastening the two terminals together. Once the terminals are fastened together, they are rotated around the pin into a position in which the slider may be pulled up to close the zipper. The disclosed devices have not supplanted the conventional design, perhaps because they deal with only some of the problems of the conventional fastener. One must still carefully interlock very small pieces in order to fasten the two terminals together. Then the free terminal must be fed through the side gap of the slider. One embodiment attempts to provide means for facilitating this feeding, but it requires an additional intricate fastening.
Another approach to the problems of conventional zippers is seen in U.S. Pat. No. 3,110,946 to K. Hara. There, a sliding fastener has two terminals each with relatively large interlocking parts at the bottom instead of the conventional pins and socket. A shortcoming of this device is that the free terminal must be inserted by the user through the side gap of the slider, while in the process of fitting together the interlocking parts. It appears that little in the way of overall ease of operation is provided by this or the Wittenberg devices; they serve mainly to emphasize the number of improvements which must be made on the conventional sliding fastener system to render it effortless and reliable.